1. Field of the Invention
The present invention relates to a process cartridge used in an image forming apparatus such as a printer, a copier or a facsimile, an assembling method, and a disassembling method thereof.
2. Background Art
Conventionally, an image forming apparatus using electrophotographic technology has adopted a process cartridge manner, in which a cartridge is formed by integrating an electrophotographic photosensitive body (the image carrier) and a process means that acts on the electrophotographic photosensitive body and the cartridge is detachable from the image forming apparatus.
In such a process cartridge, a first casing for supporting at least the electrophotographic photosensitive body, and a second casing for supporting at least the developing device are rotatably coupled by a coupling pin. At this time, in order to prevent the coupling pin from separating from the first casing and the second casing, the coupling pin is press-fit into at least one of the first casing and the second casing, and the coupling pin is attached to the first casing and the second casing in a press-fit manner.
In addition, in the process cartridge having the first casing and the second casing coupled by the coupling pin, in order to prevent the coupling pin from being pulled out by inadvertently a user, the coupling pin is press-fit into the first casing and the second casing, a cover for covering an end of the coupling pin is provided in an insertion hole for the coupling pin, and the cover is welded to conceal the coupling pin (for example, refer to JP-A-11-15354).
For example, however, as shown in FIG. 48, in case that the coupling pin 100 is attached to both sides of the first casing 102 and the second casing 104 in a press-fit manner, the pressure generates cracks 108 around three press-fit portions 106A, 106B, and 106C of the first casing 102 and the second casing 104, which causes problems that the first casing 102 and the second casing 104 are damaged, further an abnormal image occurs. Further, as shown in FIG. 48, one portion of the second casing 104 is inserted into two portions of the first casing 102. The same problems occur when the coupling pin is attached to one of the first casing and the second casing in a press-fit manner.
In addition, in case that the cover is welded so as to prevent the coupling pin from being pulled out inadvertently by a user, it becomes difficult to separate the coupling pin from the first casing and the second casing during recycling. This leads to a degraded efficiency of recycling.